Exception Handling Best Practices

Robust exception handling is essential for maintaining application stability and auditability. Following standard best practices prevents resource leaks, avoids duplicated logging, and keeps error layers clean.

The Log-and-Throw Anti-Pattern

A common mistake in Java development is logging an exception and then throwing it again:

// Anti-pattern: Log and Throw
catch (IOException e) {
    logger.error("Failed to read file", e);
    throw e;
}

This causes the exception to be logged multiple times as it propagates up the call stack, cluttering the log files and complicating debugging. The rule of thumb is: Log OR Throw. If you throw, let the calling method log it.

Common Pitfalls

• Swallowing Exceptions: Leaving catch blocks empty, which hides runtime bugs.
• Using printStackTrace() in Production: Using e.printStackTrace() instead of a logger. This writes to standard output, which is not redirected to log files and can cause thread blocking.

Best Practices

• Catch Specific Exception Types: Avoid catch-all catch (Exception e) blocks when specific exceptions can be handled individually.
• Use Try-With-Resources: Always manage resource cleanup using try-with-resources to prevent memory and file descriptor leaks.

Interview-Relevant Information